In 2003 I installed a used Heart (Xantrex) Freedom 20 and it has worked perfectly since then. The Freedom 20 was built in 1996/1997 and lightly used before I purchased it. SO - it has worked perfectly for about 13 years.

Installed about five feet behind and two feet above the Yanmar 4JH2E - warm and dry. Lots of good air circulation around it.